Review: Samsung 960 Evo SSD

Last year we reviewed Samsung’s 960 Pro drives and concluded they were amazingly fast, but overkill for most people, especially for the price. Well, Samsung’s 960 Evo has now arrived to provide a similar level of performance for a far more sensible price – and we can forestall any speculation by saying it’s a winning combination. With a few caveats.Like the 960 Pro family, the 960 Evo drives use the M.2 NVMe specification. They’re once again small, black and covered by two smart-looking stickers (the latter aren’t just there for show; they help with thermal performance too). You also benefit from the same 256-bit AES encryption – you can portion off a section of the drive to be password-protected and hidden from the OS, for instance – and the Samsung Magician tool that lets you check the drive’s health and upgrade firmware.

Where the two families start to diverge is price, although this remains volatile, if you’ll excuse the pun. The cheapest 960 Pro drive – the 512GB version – cost $449 when we went to press last month. Compare that to $329 for the 500GB Evo. And remember there’s no 256GB model, so $449 is your “price of entry” into the 960 Pro family. By comparison, you can buy the 250GB version of the 960 Evo for around $179. Where the Evo range can’t match its sibling is top capacity: a 1GB 960 Evo is the most you can hope for, which is half the Pro’s 2GB.

As with previous Samsung Evo SSDs, the 960 Evo family is distinguished from the Pro range by the use of TLC NAND, where three bits of data are stored in each memory cell rather than two as in the 960 Pro. Consequently, the Evo drives are rated to write only half the total data of the Pro drives, and have a three-year warranty rather than the Pro drives’ five-year warranty. Also, while the increased data density makes for a cheaper drive, it reduces write speed.

To mitigate this, the Evo drives employ SLC caching to increase short-term write speed. So while the 1TB drive can hit a claimed maximum 1,900MB/sec sequential write speeds, it drops to 1,200MB/sec after the 42GB of SLC cache is filled. That’s for the 500GB version. The 250GB model maxes out at 1,500MB/sec write and drops precipitously to 300MB/sec after 13GB has been written.

This has a knock-on effect when it comes to random read and write performance. The 500GB drive manages 330K IOPS for a few seconds, but quickly dropped to an average of 100K IOPS in our Iometer test. That’s still mighty fast, mind. Otherwise, in all our tests, the 960 Evo lived up to expectations, hitting the speeds Samsung claims and only trailing slightly behind the 960 Pro.

Now, during testing we encountered an oddity – a pleasingly surprising oddity. While Samsung claim a top sequential read speed of around 1,900MB/sec for the 1TB 960 Evo, we recorded an average of 3,400MB/ sec. That’s just shy of the 960 Pro’s maximum speed of 3,500MB/sec! Furthermore, write speeds also well exceeded claimed speeds, consistently recording 1,900MB/s, compared to a claimed maximum of 1,500MB/s. This was on a testbed based on a Skylake i7 on a Z170 motherboard. Testing with default Microsoft Windows SSD drivers and then Samsung’s own drivers yielded the same results.

Even stranger, in this same testbed sits the supposedly superior 960 Pro, and its results matched the 960 Evo when we first ran benchtests. That in itself is less of a surprise as the 960 Pro was delivering numbers that matched the manufacturer’s claims, but a little later on in the testing process we cloned the Windows OS to the 960 Pro and that caused its speeds to actually drop! Now, the OS 960 Pro records just shy of 2,900MB/sec, with the 960 Evo faster at 3,400MB/sec read! We queried this with Samsung and were told that cloning a SATA drive to an NVMe drive can cause this – but we were cloning from an NVMe SSD – Samsung’s earlier 950 Pro, no less. We can’t explain these results, and it may be a peculiarity of the testbed configuration but everything is stock on that testbed so this little mystery remains up in the air. Annoyingly, it means that we can’t, then, assure you that you will see such oddities, or will simply see advertised speeds with no issues.

As with the 960 Pro, the real-world impact of all that performance is minimal. In the app-loading test of PCMark, our manual game load tests and Windows boot tests all showed virtually no increase over SATA SSDs. As a result, it’s worth considering spending your money on a slower drive with a larger capacity if application performance is your top priority.

In particular, you may want to consider the SATA version of the Samsung 850 Evo. It fell behind in any benchmark looking for consistent write speeds – for example, it hit 30.7MB/sec in PCMark 7’s import pictures benchmark, compared to 34.6MB/sec for the 960 Evo – but you have to question whether such differences will be noticed in real-world use. Likewise, its cold boot-time was 18.3 seconds to 17.7 seconds, leaving 0.6 seconds of extra wait time. Boot times were almost identical with the 960 Pro, which may in part be explained by the similarity in read speeds between the 960 Pro and 960 Evo that we saw in our testing, but mostly because the boot bottlenecks lie elsewhere.

With prices of the drives bouncing around, it’s well worth making a shortlist of your chosen drives and striking when you see the right combination of price and capacity for your needs. If you can find the 960 Evo 500GB for around $300, it strikes a near-perfect balance of performance and price, while still maintaining decent capacity. When it comes to sheer bang-per-buck, this is the SSD to buy.